// Licensed to Apache Software Foundation(ASF) under one or more contributor
// license agreements. See the NOTICE file distributed with
// this work for additional information regarding copyright
// ownership. Apache Software Foundation(ASF) licenses this file to you under
// the Apache License, Version 2.0 (the "License"); you may
// not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an
// "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
// KIND, either express or implied.  See the License for the
// specific language governing permissions and limitations
// under the License.

package util

import (
	"regexp"
	"strings"
)

var pattern = regexp.MustCompile(`[^\w@%+=:,./-]`)

// ShellQuote returns a shell-escaped version of the string s. The returned value
// is a string that can safely be used as one token in a shell command line.
func ShellQuote(s string) string {
	if len(s) == 0 {
		return "''"
	}
	if pattern.MatchString(s) {
		return "'" + strings.Replace(s, "'", "'\"'\"'", -1) + "'"
	}

	return s
}
